<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<style>
    .box{
        width: 100%;
        height: 200px;
        background-color: pink;
        font-size: 16px;
        color: #000;
    }
    .box2{
        width: 1000px;
        height: 200px;
        background-color: yellowgreen;
        font-size: 16px;
        color: #000;
    }
</style>
<body>
    <div class="box">文字文字</div>
    <div class="box2">文字文字</div>
</body>
</html>